Electronic devices, such as cell phones and PDA's, typically include several individually packaged integrated circuits with different functions. To facilitate space savings and, hence, significant down-sizing of electronic gadgets, 3D packaging solutions may be utilized.
One 3D packaging technique is a “System-in-a-Package” (SIP) approach. SIP refers to a semiconductor device that incorporates multiple die that make up a complete electronic system into a single package. SIP sometimes employs die stacking, which mounts die on top of one another and interconnects them.
Another form of 3-D packaging is package-in-a-package stacking. Package-in-package stacking involves flipping and stacking a tested package onto a base package, with subsequent interconnection via wire bonding. A package-in-package requires the tested package to be fully encapsulated prior to assembly within the base package.